Hydrogen as an energy storage medium for residential photovoltaic systems

Hydrogen and conventional battery energy storage were assessed separately, and in combination, in an advanced stand-alone solar-photovoltaic residential system. A well-designed, single-story dwelling, located in Southeast Florida, was used as a model with all household loads served by the solar energy system. Favorable far-term equipment cost projections were generally used. For daily cycling loads, battery storage was found to be an economic approach. However, hydrogen is shown to be increasingly attractive as requirements for extended days of storage are addressed for non-insolation periods. Also, water heating needs can be readily met from water electrolyzer and fuel cell subsystem rejected heat. Life-cycle costs are shown to be acceptable in the far-term, with the sale of excess power to the utility. Designing the system to supply power to the utility on-peak (at premium rates) further improves the life-cycle costs.